O2 won't erect a mast just so you can use their wifi. The idea is that putting more masts up quickly will lead to improved network coverage.
O2 could erect a WiFi mast near my house as well. But I doubt they will. O2 WiFi is a free service that enables you to log onto WiFi when you are out and about(City Centre, retail parks concert venues etc) it is not a substitiute for home WiFi (which you pay for).
If you need WiFi at home then your best option is to go to one of the many providers and have it installed.
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